\\[-1.8ex] Soil Heterogeneity & $-$0.108$^{*}$ & $-$0.034 & $-$0.049$^{**}$ & $-$0.044$^{**}$ & $-$0.046$^{**}$ & $-$0.049$^{***}$ \\ 
  & (0.065) & (0.024) & (0.022) & (0.022) & (0.020) & (0.019) \\ 
\\[-1.8ex] 
Oster $\delta$ for $\beta=0$ &  & 1.34 & 2.19 & 1.96 & 2.04 & 2.22 \\ 
Observations & 23,431 & 23,431 & 23,431 & 23,431 & 23,431 & 23,369 \\ 
R$^{2}$ & 0.003 & 0.793 & 0.802 & 0.813 & 0.816 & 0.819 \\ 
